1. Field of the Invention
The present invention relates to a light source device which radiates illumination light.
2. Description of the Related Art
A related art of a light source device which radiates illumination light is disclosed in, for example, US2005/0107032A1. A light emitting device suggested in US2005/0107032A1 is a combination of light emitting units each including a laser light source, a light guide which includes an optical fiber, and a wavelength converting member. In a first light emitting unit of this light emitting device, a blue laser light source is provided at the proximal end of the light guide which includes the optical fiber, and the wavelength converting member is provided at the distal end of the light guide. Laser light emitted from the blue laser light source is guided to the distal end by the light guide, and the wavelength of the laser light is converted by the wavelength converting member at the distal end of the light guide. Further, a laser light source having a wavelength shorter than that of blue, a light guide, and a wavelength converting member are used to constitute a second light emitting unit. US2005/0107032A1 discloses that the first light emitting unit and the second light emitting unit are combined to constitute the light emitting device so that color rendering properties are improved as compared to those in the case of the single first light emitting unit.
Recently, in connection with light source devices used for observation in, for example, endoscopes, efforts have been made to improve the visibility of an observation target by properly selecting brightness, a peak wavelength, an emitted color, i.e. a spectrum shape, a radiation angle, and an emission pattern shape of illumination light depending on the purpose of observation.
In the light source device according to the conventional art in US2005/0107032A1, it is necessary to prepare different kinds of light emitting units in the body of the light source device, and adjust the combination of the light emitting units to be used to a purpose, in order to obtain illumination light suited to the purpose. However, the preparation of a large number of light emitting units in the body of the light source device is not preferable in respect of costs and storage locations.